Information provision device, information provision method, and recording medium

ABSTRACT

An information provision device includes an image display to display a for-driver information image to a driver of a mobile object, an interface to obtain at least one of (i) movement information of the mobile object and (ii) position information of the mobile object, and a circuitry to control display of the for-driver information image based on a viewpoint position of the driver that is detected by a viewpoint detector. The circuitry changes a display position of the for-driver information image so as to change a perception distance of the for-driver information image for the driver due to motion parallax based on the at least one of movement information and position information of the mobile object that is obtained.

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application is based on and claims priority pursuant to 35U.S.C. § 119(a) to Japanese Patent Application Nos. 2015-089238, filedon Apr. 24, 2015, and 2015-092590, filed on Apr. 30, 2015, in the JapanPatent Office, the entire disclosure of which is hereby incorporated byreference herein.

BACKGROUND

Technical Field

Embodiments of the present invention relate to an information provisiondevice, an information provision method, and a non-transitory recordingmedium storing an information-provision control program.

Description of the Related Art

An information provision device for which a heads-up display (HUD) orthe like is provided is known in the art, and such a HUD projects animage to provide information to the driver of a mobile object such as avehicle, ship, aircraft, and a steel-collar worker (robot).

JP-4686586-B discloses a HUD that projects an image light to a frontwindshield or the like (light transmission member) to display an imageover the sight ahead of the vehicle (mobile object) which is visuallyrecognized by the driver through the front windshield. Such a HUDdisplays an arrow indicating the direction of travel, and an objectindicating, for example, the speed, caution, and warning over the sightahead of the vehicle, as a virtual image. The HUD includes a pointdetector (viewpoint detector) that captures the driver to detect theposition of a single eye of the driver, and changes the respectivepositions of the objects in the virtual image according to the result ofthe detection. More specifically, the HUD changes the amounts ofmovement of the objects in the virtual image when the driver has movedhis or her head and the location of the viewpoint (the position of thesingle eye) has moved. Accordingly, the driver perceives the objects asif the display position of the objects in the depth direction(subjective depth dimension) vary due to the motion parallax.

SUMMARY

Embodiments of the present invention include an information provisiondevice, which includes an image display to display a for-driverinformation image to a driver of a mobile object, an interface to obtainat least one of (i) movement information of the mobile object and (ii)position information of the mobile object, and circuitry to controldisplay of the for-driver information image based on a viewpointposition of the driver that is detected by a viewpoint detector. Thecircuitry changes a display position of the for-driver information imageso as to change a perception distance of the for-driver informationimage for the driver due to motion parallax based on the at least one ofmovement information and position information of the mobile object thatis obtained.

In one example, in the information provision device, the circuitryfurther determines whether the detection result of the viewpointdetector satisfies a predetermined abnormal condition, and performsabnormality handling operation instead of performing the display controlof the for-driver information.

Embodiments of the present invention include an information provisiondevice, which includes an image display to display a for-driverinformation image to a driver of a mobile object, and circuitry tocontrol display of the for-driver information image based on a viewpointposition of the driver that is detected by a viewpoint detector. Thecircuitry changes a display position of the for-driver information imageso as to change a perception distance of the for-driver informationimage for the driver due to motion parallax. The circuitry determineswhether the detection result of the viewpoint detector satisfies apredetermined abnormal condition, and performs abnormality handlingoperation instead of performing the display control of the for-driverinformation.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages and features thereof can be readily obtained and understoodfrom the following detailed description with reference to theaccompanying drawings.

FIG. 1 is a schematic diagram of an example virtual image displayed in adisplay area over the sight ahead of the vehicle viewed by a driverthrough the front windshield, according to an embodiment of the presentinvention.

FIG. 2 is a schematic diagram of the configuration of a car for which anon-vehicle HUD according to an embodiment of the present invention isprovided.

FIG. 3 is a schematic diagram of the internal structure of an on-vehicleHUD according to an example embodiment of the present invention.

FIG. 4 is a block diagram illustrating the hardware configuration of acontrol system of an on-vehicle HUD according to an example of thepresent invention.

FIG. 5 is a block diagram illustrating an outline of the configurationof an information provision system for a driver, according to anembodiment of the present invention.

FIG. 6 is a schematic block diagram illustrating the hardwareconfiguration of an object recognition device in an informationprovision system for a driver, according to an embodiment of the presentinvention.

FIG. 7 is a schematic block diagram illustrating the hardwareconfiguration of an image controller in an on-vehicle HUD according toan embodiment of the present invention.

FIG. 8 is a schematic diagram illustrating a method of processing avirtual image with a depth perception that is created by a motionparallax, according to an embodiment of the present invention.

FIG. 9 is a flowchart illustrating operation of controlling display of afollowing-distance presenting image in a first example.

FIG. 10 is a display example of the following-distance presenting imagein the case of a low speed vehicle in the first example.

FIG. 11 is a display example of the following-distance presenting imagein the case of a high speed vehicle in the first example.

FIG. 12 is an explanatory diagram illustrating the difference in theperception distance of the following-distance presenting image betweenthe display example illustrated in FIG. 10 and the display exampleillustrated in FIG. 11.

FIG. 13 is a flowchart illustrating operation of controlling display ofa following-distance presenting image in a second example.

FIG. 14A is a display example of a normal following-distance presentingimage when the vehicle is running on a highway.

FIG. 14B is a display example of the following-distance presenting imagewhen the vehicle is passing through a sag (where congestion isgenerated) on a highway.

FIG. 15 is a flowchart illustrating operation of controlling display ofthe following-distance presenting image in a third example.

FIG. 16A is a display example of the following-distance presenting imagein the case of a low speed vehicle.

FIG. 16B is a display example of the following-distance presenting imagein the case of a high speed vehicle.

FIG. 17 is a flowchart illustrating operation of handling abnormality ina first example.

FIG. 18 is a flowchart illustrating operation of handling abnormality ina second example.

FIG. 19 is a flowchart illustrating operation of handling abnormality ina third example.

The accompanying drawings are intended to depict example embodiments ofthe present invention and should not be interpreted to limit the scopethereof. The accompanying drawings are not to be considered as drawn toscale unless explicitly noted.

DETAILED DESCRIPTION

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“includes” and/or “including”, when used in this specification, specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

In describing example embodiments illustrated in the drawings, specificterminology is employed for the sake of clarity. However, the presentdisclosure is not intended to be limited to the specific terminology soselected and it is to be understood that each specific element includesall technical equivalents that operate in a similar manner.

An information provision system for a driver, which serves as aninformation provision device, to which an on-vehicle heads-up display(HUD) according to an embodiment of the present invention is applied, isdescribed.

FIG. 1 is a schematic diagram of an example virtual image G displayed ina display area 700 over the sight ahead of the vehicle 301 viewed by adriver 300 through a front windshield 302, according to the presentembodiment.

FIG. 2 is a schematic diagram of a car for which the on-vehicle HUDaccording to the present example embodiment is provided.

FIG. 3 is a schematic diagram of the internal structure of theon-vehicle HUD according to the present example embodiment.

An on-vehicle HUD 200 according to the present embodiment is installed,for example, in the dashboard of the car 301 that serves as a mobileobject. The projection light L, which is the light for projecting animage, that is emitted from the on-vehicle HUD 200 disposed in thedashboard is reflected at a front windshield 302 that serves as a lighttransmission member, and is headed for a driver 300. Accordingly, thedriver 300 can visually recognize a HUD display image such as anavigation image, which will be described later, as a virtual image.Note that a combiner that serves as a light transmission member may bedisposed on the inner wall of the front windshield 302, and the driver300 may visually recognizes a virtual image formed by the projectionlight L that is reflected by the combiner.

In the present embodiment, the optical system or the like of theon-vehicle HUD 200 is configured such that the distance from the driver300 to a virtual image G becomes equal to or longer than 5 meters (m).In the known on-vehicle HUDs, the distance from the driver 300 to thevirtual image G is about 2 m. Usually, the driver 300 observes a pointat infinity ahead of the vehicle, or observes a preceding vehicle a fewtens of meters ahead of the vehicle. When the driver 300 who is focusingon an object in the distance attempts to visually recognize the virtualimage G that is two meters ahead of the vehicle, the crystalline lensesof the eyes need to be moved widely because the focal length greatlyvaries. In such cases, the time required to adjust the focus of the eyesand focus on the virtual image G becomes longer, and it takes a longtime to recognize the detail of the virtual image G. What is worse, theeyes of the driver 300 tend to get tired. Moreover, it is difficult forthe driver to realize the detail of the virtual image G, and it isdifficult to use the virtual image G to appropriately provideinformation to the driver.

If the distance to the virtual image G is equal to or longer than 5 m asin the present embodiment, the amount of movement in the crystallinelenses of the eyes is reduced to a less amount of movement than thebackground art, and the time required to adjust the focus of the eyesand focus on the virtual image G becomes shorter. Accordingly, thedriver 300 can recognize the detail of the virtual image G at an earlystage, and the possible tiredness of the eyes of the driver 300 can bereduced. Moreover, it becomes easier for the driver to realize thedetail of the virtual image G, and it is easy to use the virtual image Gto appropriately provide information to the driver.

When the distance to the virtual image G is about 2 m, the driverattempts to adjust the focal point of the eyes on the virtual image G,usually through the convergence motion. The convergence motion is amajor factor in achieving the desired sense of distance or depthperception to an object to be visually recognized. In the presentembodiment, as will be described later, the display is controlled suchthat the perception distance of the virtual image G will be perceived bymotion parallax. If the convergence motion occurs to the eyes to focuson the virtual image G when the display is controlled as above, thesense of distance (change in perception distance) or the depthperception (difference in perception distance), which are expected to bebrought by a motion parallax, cannot be perceived as desired.Accordingly, if the convergence motion occurs to the eyes, the drivercannot perceive the information as intended by the configurationaccording to the present embodiment. Note that such configuration willbe described later, and the effect is estimated in view of thedifference or change in the perception distance of an image.

When the distance to the virtual image G is equal to or greater than 5m, the driver can focus on the virtual image G with almost noconvergence motion in the eyes. Accordingly, the sense of distance(change in perception distance) or the depth perception (difference inperception distance), which are expected to be brought by motionparallax, can be perceived as desired in absence of the convergencemotion of the eyes. As described above, according to the presentembodiment, the driver perceive the information as intended in view ofthe sense of distance or depth perception of an image.

The on-vehicle HUD 200 includes a HUD 230, and the HUD 230 includes red,green, and blue laser beam sources 201R, 201G, and 201B, collimatorlenses 202, 203, and 204 that are provided for the laser beam sources201R, 201G, and 201B, respectively, two dichroic mirrors 205 and 206, alight quantity adjuster 207, an optical scanner 208, a free-form surfacemirror 209, a microlens array 210 that serves as a light dispersingmember, and a projector mirror 211 that serves as a light reflectingmember. A light source unit 220 according to the present embodimentincludes the laser beam sources 201R, 201G, and 201B, the collimatorlenses 202, 203, and 204, and the dichroic mirrors 205 and 206, andthese elements are unitized by an optical housing.

Each of the laser beam sources 201R, 201G, and 201B may be an LD(semiconductor laser element). The wavelength of the laser-beam bundlethat is emitted from the red laser beam source 201R is, for example, 640nanometer (nm). The wavelength of the laser-beam bundle that is emittedfrom the green laser beam source 201G is, for example, 530 nm. Thewavelength of the laser-beam bundle that is emitted from the blue laserbeam source 201B is, for example, 445 nm.

The on-vehicle HUD 200 according to the present embodiment projects theintermediate image formed on the microlens array 210 onto the frontwindshield 302 of the vehicle 301, such that the driver 300 can visuallyrecognize the magnified intermediate image as a virtual image G. Thelaser beams of RGB colors emitted from the laser beam sources 201R,201G, and 201B are approximately collimated by the collimator lenses202, 203, and 204, and are combined by the two dichroic mirrors 205 and206. The light quantity of the combined laser beam is adjusted by thelight quantity adjuster 207, and then the adjusted laser beam istwo-dimensionally scanned by the mirror of the optical scanner 208. Thescanned light L′ that is two-dimensionally scanned by the opticalscanner 208 is reflected by the free-form surface mirror 209 so as tocorrect the distortion, and then is collected and condensed to themicrolens array 210. Accordingly, an intermediate image is drawn.

In the present embodiment, the microlens array 210 is used as a lightdispersing member that individually disperses and emits the laser-beambundle of each pixel of the intermediate image (i.e., each point of theintermediate image). However, any other light dispersing member may beused. Alternatively, a liquid crystal display (LCD) or a vacuumfluorescent display (VFD) may be used as a method of forming theintermediate image G′.

However, in order to display the virtual image G with a wide dimensionand high brightness, the laser scanning system is desired as in thepresent embodiment.

In the systems where an LCD or VFD is used, a non-image area of thedisplay area on which the virtual image G is displayed is slightlyirradiated with light, and it is difficult to completely shut such lightto the non-image area. For this reason, in the systems where an LCD orVFD is used, the non-image area disturbs the visual recognizability ofthe sight ahead of the vehicle 301. By contrast, if a laser scanningsystem is adopted as in the present embodiment, the light thatirradiates the non-image area of the display area on which the virtualimage G is displayed can be completely shut by switching off the laserbeam sources 201R, 201G, and 201B. For this reason, if a laser scanningsystem is adopted as in the present embodiment, the non-image area doesnot disturb the visual recognizability of the sight ahead of the vehicle301 as the light from the on-vehicle HUD 200 that may irradiate thenon-image area can be completely shut.

When the degree of warning is to be enhanced by gradually increasing thebrightness of the warning image that alerts the driver, the displayneeds to be controlled such that only the brightness of the warningimage gradually increases among the various kinds of images displayed inthe display area 700. Again, the laser scanning system is suitable forsuch cases where the display is controlled such that the brightness of apart of the images displayed in the display area 700 is selectivelyincreased. In the systems with the LCD or the VFD, the brightness of theimages other than the warning image also increases among the variouskinds of images displayed in the display area 700. In such cases, thedifference in brightness cannot be increased between the warning imageand the other images. Accordingly, the degree of the warning cannot besufficiently enhanced by gradually increasing the brightness of thewarning image.

The optical scanner 208 uses a known actuator driver system such as amicro-electromechanical systems (MEMS) to incline the mirror to themain-scanning direction and the sub-scanning direction, andtwo-dimensionally scans (raster-scans) the laser beams that enter themirror. The mirror is controlled in synchronization with the timing atwhich the laser beam sources 201R, 201G, and 201B emit light. Theoptical scanner 208 may be configured, for example, by a mirror systemthat includes two mirrors that pivot or rotate around the two axes thatare orthogonal to each other.

FIG. 4 is a block diagram illustrating the hardware configuration of acontrol system of the on-vehicle HUD 200 according to the presentembodiment.

The control system of the on-vehicle HUD 200 includes a fieldprogrammable gate array (FPGA) 251, a central processing unit (CPU) 252,a read only memory (ROM) 253, a random access memory (RAM) 254, aninterface (I/F) 255, a bus line 256, a laser diode (LD) driver 257, anda MEMS controller 258. The FPGA 251 uses the LD driver 257 to controlthe operation of the laser beam sources 201R, 201G, and 201B of thelight source unit 220. Moreover, the FPGA 251 uses the MEMS controller258 to controlling the operation of a MEMS 208 a of the optical scanner208. The CPU 252 controls the operation of the on-vehicle HUD 200. TheROM 253 stores various kinds of programs such as an image processingprogram that is executed by the CPU 252 to control the operation of theon-vehicle HUD 200. The RAM 254 is mainly used as a working area inwhich the CPU 252 executes a program. The I/F 255 allows the on-vehicleHUD 200 to communicate with an external controller such as a controllerarea network (CAN) of the vehicle 301. For example, the on-vehicle HUD200 is connected to an object recognition device 100, a vehiclenavigation device 400, and various kinds of sensor device 500 throughthe CAN of the vehicle 301. The object recognition device 100, thevehicle navigation device 400, and the sensor device 500 will bedescribed later in detail.

FIG. 5 is a block diagram illustrating an outline of the configurationof an information provision system for a driver according to the presentembodiment.

In the present embodiment, as an information acquisition unit thatobtains for-driver information to be provided to a driver via a virtualimage G, the object recognition device 100, the vehicle navigationdevice 400, and the sensor device 500 are provided. The on-vehicle HUD200 according to the present embodiment includes the HUD 230 that servesas an image-light projection device, and the image controller 250including a processor serving as a display controller. The informationacquisition unit according to the present embodiment is provided for thevehicle 301, but the vehicle 301 may use an external informationacquisition unit to obtain the information input from the externalinformation acquisition unit through a means of communication.

FIG. 6 is a schematic block diagram illustrating the hardwareconfiguration of the object recognition device 100 according to thepresent embodiment.

The object recognition device 100 according to the present embodimentincludes a stereo camera 110 that captures an area ahead of the vehicle301 as a captured area, and an information processing unit 120 thatperforms image processing to recognize a prescribed object existing inthe captured area according to the image data captured by the stereocamera 110. Note that the stereo camera 110 may be replaced with acombination of a monocular camera that serves as an imaging unit, and alaser radar (millimeter-wave radar) that serves as a distance measuringequipment.

The stereo camera 110 includes a first camera unit 110A for a left eyeand a second camera unit 110B for a right eye, and these two cameraunits are combined together in parallel. Each of the camera unit 110Aand the camera unit 110B includes a lens 115, an image sensor 116, and asensor controller 117. The image sensor 116 may be composed of, forexample, a charge-coupled device (CCD) or a complementary metal oxidesemiconductor (CMOS). The sensor controller 117 controls, for example,the exposure of the image sensor 116, the reading of an image, thecommunication with an external circuit, and the sending of the imagedata. The stereo camera 110 is disposed near the rear-view mirrorprovided for the front windshield 302 of the vehicle 301.

The information processing unit 120 includes a data bus line 121, aserial bus line 122, central processing unit (CPU) 123, a fieldprogrammable gate array (FPGA) 124, a read only memory (ROM) 125, arandom access memory (RAM) 126, a serial interface (IF) 127, and a datainterface (IF) 128.

The stereo camera 110 is connected to the information processing unit120 through the data bus line 121 and the serial bus line 122. The CPU123 controls, for example, the sensor controllers 117 of the stereocamera 110, the entire operation of the information processing unit 120,and the execution of image processing. The brightness image data of theimages that are captured by the image sensors 116 of the camera unit110A and the camera unit 110B are written into the RAM 126 of theinformation processing unit 120 through the data bus line 121. Thecontrol data for changing the exposure value of a sensor from the CPU123 or the FPGA 124, the control data for changing the image readingparameter, various kinds of setting data, or the like are transmittedand received through the serial bus line 122.

The FPGA 124 performs processing that needs to be done in real time onthe image data stored in the RANI 126, such as gamma correction,distortion correction (collimation of an image on the right and left),parallax computation using block matching, to generate a parallax image,and writes the generated parallax image into the RAM 18 again. In theROM 125, a recognition program is stored for recognizing a prescribedobject including a three-dimensional object such as a vehicle orpedestrian, a boundary line for lanes such as a white line on the road,and a curbstone or median strip arranged by the roadside. Therecognition program is an example of an image processing program.

The CPU 123 obtains CAN information such as vehicle speed, acceleration,a rudder angle, and a yaw rate from the sensor device 500 through thedata interface (IF) 128. The data interface 128 may be, for example, aCAN of the vehicle 301. Then, the CPU 123 performs image processingusing the brightness image and parallax image stored in the RANI 126,according to the recognition program stored in the ROM 125, andrecognizes an object such as a preceding vehicle 350 or a traffic laneline.

The recognition-result data of an object is supplied, for example, tothe image controller 250 and an external device such as a vehicle drivecontrol unit, through the serial I/F 127. The vehicle drive control unituses the recognition-result data of an object to perform brake control,speed control, steering control, or the like of the vehicle 301, andimplements, for example, cruise control in which the vehicle 301automatically tracks a preceding vehicle so as to maintain a prescribedfollowing distance, and an automatic brake control in which thecollision with an obstacle ahead of the vehicle is avoided orattenuated.

The vehicle navigation device 400 according to the present embodimentmay be any known vehicle navigation device provided for a vehicle or thelike. The vehicle navigation device 400 outputs information used forgenerating a route navigation image to be displayed on a virtual imageG, and the information output from the vehicle navigation device 400 isinput to the image controller 250. The information that is output fromthe vehicle navigation device 400 includes, for example, as illustratedin FIG. 1, images indicating the number of the lanes (traffic lanes) ofthe road on which the vehicle 301 is traveling, the distance to the nextpoint where the direction is to be changed (for example, a right turn,left turn, and a branch point), and the direction to which the path isto be changed next in order. As such information is input from thevehicle navigation device 400 to the image controller 250, under thecontrol of the image controller 250, the on-vehicle HUD 200 displaysnavigation images such as a lane indicator image 711, afollowing-distance presenting image 712, a path indicator image 721, aremaining distance indicator image 722, an intersection or the like nameindicator image 723, on an upper display area A of the display area 700.

In the example image illustrated in FIG. 1, images indicatingroad-specific information (e.g., road name, and speed limit) isdisplayed on a lower display area B of the display area 700. Theroad-specific information is also input from the vehicle navigationdevice 400 to the image controller 250. The image controller 250 usesthe on-vehicle HUD 200 to display the road-specific information such asa road-name display image 701, a speed limit display image 702, and ano-passing zone display image 703 on the lower display area B of thedisplay area 700.

The sensor device 500 according to the present embodiment includes oneor two or more sensors that detect various kinds of information such asthe behavior of the vehicle 301, the state of the vehicle 301, and theenvironment around the vehicle 301. The sensor device 500 outputssensing information used for generating an image to be displayed as avirtual image G, and the information output from the sensor device 500is input to the image controller 250. For example, in the example imageillustrated in FIG. 1, a vehicle speed display image 704 indicating thespeed of the vehicle 301 (i.e., the textual image of “83 km/h” inFIG. 1) is displayed on the lower display area B of the display area700. The vehicle-speed information included in the CAN information ofthe vehicle 301 is input from the sensor device 500 to the imagecontroller 250, and the image controller 250 controls the on-vehicle HUD200 to display the textual image indicating the vehicle speed on thelower display area B of the display area 700.

In addition to the sensor that detects the speed of the vehicle 301, thesensor device 500 includes, for example, a laser radar or imaging devicethat detects the distance from another vehicle, a pedestrian, orconstruction such as a guard rail and a utility pole, which exist around(ahead of, on the side of, in the rear of) the vehicle 301, a sensorthat detects the external environmental information (e.g., outside airtemperature, brightness, and weather) of the vehicle 301, a sensor thatdetects the driving action (e.g., braking action, and the degree ofacceleration) of the driver 300, a sensor that senses the amount of thefuel remaining in the fuel tank of the vehicle 301, and a sensor thatsenses the state of various kinds of vehicle-borne equipment such as anengine and a battery. As such information is detected by the sensordevice 500 and sent to the image controller 250, the on-vehicle HUD 200can display the information as a virtual image G. Accordingly, theinformation can be provided to the driver 300.

FIG. 7 is a schematic block diagram illustrating the hardwareconfiguration of the image controller 250.

In the image controller 250, a CPU 251, a RAM 252, a ROM 253, an inputdata interface (I/F) 254, and output data interface (I/F) 255 areconnected to each other via a data bus line. To the input data I/F 254,for example, various kinds of recognition-result data output from theobject recognition device 100, the sensing information output from thesensor device 500, and various kinds of information output from thevehicle navigation device 400 are input. From the output data I/F 255,for example, a control signal for the on-vehicle HUD 200 is output. TheCPU 251 executes various kinds of computer program such as aninformation-provision control program, which is stored, for example, inthe ROM 253, to control the image controller 250 to perform variouskinds of control and process as will be described later.

Next, a virtual image G that is displayed by the on-vehicle HUD 200according to the present embodiment is described.

In the present embodiment, for-driver information that the on-vehicleHUD 200 provides for the driver 300 via a virtual image G may be anyinformation. In the present embodiment, the for-driver information isbroadly divided into passive information and active information.

The passive information is the information to be passively recognized bythe driver 300 at the timing when a prescribed information provisioncondition is met. Accordingly, the passive information includes theinformation to be provided to the driver 300 at the timing when theon-vehicle HUD 200 is configured, and the passive information includesthe information whose provision timing has a certain relation with thedetail of the information. The passive information includes, forexample, security information for driving, and route navigationinformation. The security information for driving includes, for example,the following-distance information indicating the distance between thevehicle 301 and the preceding vehicle 350 (i.e., a following-distancepresenting image 712 as will be described later), and informationincluding urgent matters for driving (e.g., warning information such asan instruction for urgent action to be taken by a driver, or attentionattracting information). The route navigation information indicates aroute to a prescribed destination, and such a route is provided to adriver by any known vehicle navigation device. The route navigationinformation includes, for example, lane information (i.e., the laneindicator image 711) indicating a lane to be taken at an upcomingintersection, and direction-change instruction information indicating adirection change to be made at the next intersection or branch pointwhere the direction is to be changed from the straight-ahead direction.The direction-change instruction information includes, for example, pathindicating information (i.e., the path indicator image 721) thatindicates the path to be taken at the next intersection or branch point,remaining distance information (i.e., the remaining distance indicatorimage 722) indicating the distance to the intersection or branch pointwhere the direction change is to be made, and name information of theintersection or branch point (i.e., the intersection or the like nameindicator image 723).

The active information is the information to be actively recognized bythe driver 300 at the timing specified by the driver himself or herself.The active information is to be provided to the driver 300 only when heor she wishes. For example, the active information includes informationwhere the timing of its provision has low or no relevance to the detailof the information. As the active information is obtained by the driver300 at the timing when he or she wishes, the active information isusually displayed for a long time or displayed continuously. Forexample, the road-specific information of the road on which the vehicle301 is traveling, the vehicle-speed information (i.e., the vehicle speeddisplay image 704) of the vehicle 301, the current-time information areincluded in the active information. The road-specific informationincludes, for example, the road-name information (i.e., the road-namedisplay image 701), the regulation information of the road such as speedlimit (i.e., the speed limit display image 702 and the no-passing zonedisplay image 703), and other kinds of information of the road usefulfor the driver.

In the present embodiment, the for-driver information, which is broadlydivided into the active information and the passive information asdescribed above, is displayed in a corresponding area of the displayarea 700 where a virtual image is displayable. More specifically, in thepresent embodiment, the display area 700 is divided into two displayareas in the up-and-down directions. Then, a passive-information imagethat corresponds to the passive information is mainly displayed in theupper display area A of the obtained three display areas, and anactive-information image that corresponds to the active information ismainly displayed in the lower display area B. Note that only some of theactive-information image may be displayed upper display area A. In suchcases, the active-information image is displayed in such a manner that ahigher priority is given to the viewability of the passive-informationimage displayed in the upper display area A.

In the present embodiment, a stereoscopic image is used as the virtualimage G that is displayed in the display area 700. More specifically,perspective images are used as the lane indicator image 711 and thefollowing-distance presenting image 712 that are displayed in the upperdisplay area A of the display area 700.

More specifically, a perspective image that is drawn by the perspectivedrawing method such that the length of the five horizontal lines of thefollowing-distance presenting image 712 becomes shorter towards theupper side and the following-distance presenting image 712 heads for asingle vanishing point. In particular, in the present embodiment, thefollowing-distance presenting image 712 is displayed such that thevanishing point approximately matches the observation point of thedriver 300. Due to this configuration, while the driver 300 is driving,he or she can easily perceive the depth of the following-distancepresenting image 712. Moreover, in the present embodiment, a perspectiveimage in which the thickness of the horizontal lines becomes thinnertowards the upper side and the brightness of the horizontal linesbecomes lower towards the upper side is used. Due to this configuration,while the driver 300 is driving, he or she can even more easily perceivethe depth of the following-distance presenting image 712.

Next, a method of creating a sense of distance or depth perception bymaking the driver perceive the distance to the virtual image G makinguse of a motion parallax is described.

In the present embodiment, a motion-parallax image is used as thevirtual image G. The motion parallax indicates the parallax that iscaused as the position of the eyes of the driver 300 (i.e., the positionof the viewpoint) moves. The driver 300 perceives the distance and depthdimension with reference to an object, which are influenced by a motionparallax due to the displacement in movement where an object closer tothe driver in the sight ahead of the vehicle appears to move in agreater amount and an object more distant from the driver in the sightahead of the vehicle appears to move in a smaller amount when theposition of the eyes of the driver 300 moves.

In the present embodiment, as illustrated in FIG. 2, a driver camera 150that monitors the positions of the eyes of the driver 300 (i.e., thelocation of the viewpoint) is disposed near the rear-view mirrorprovided for the front windshield 302 of the vehicle 301. In order tomonitor the motion of the driver 300 in the up-and-down andright-and-left directions accurately, it is desired that the drivercamera 150 be disposed around the median line drawn from the driver 300who sits in the driver's seat. Moreover, it is desired that the drivercamera 150 be disposed, for example, on an upper side so as not toobstruct the view of the driver 300.

The driver camera 150 is a monocular camera that is configured tocapture an area where the driver 300 who sits in the driver's seat andis driving the vehicle is expected to move his/her head. In a similarmanner to the camera unit 110A and the camera unit 110B provided for thestereo camera 110, the driver camera 150 includes, for example, a lens,an image sensor, and a sensor controller. A stereo camera may be used asthe driver camera 150 in order to keep track of the position of the eyesof the driver in the forward and backward directions.

The brightness image data of the images captured by the driver camera150 is input to image controller 250. The image controller 250 uses theCPU 251 to execute an information-provision control program stored inthe ROM 253 or the like, and recognizes the position of the eyes of thedriver 300 based on the brightness image data obtained from the drivercamera 150. In the present embodiment, the position of the head of thedriver 300 is recognized in a simplified manner based on the brightnessimage data obtained from the driver camera 150, and the position of theeyes of the driver 300 is estimated based on the results of therecognition. Note that any desired known recognition method may beadopted as a method of recognizing the position of the head of thedriver 300.

Examples include a method in which a color of a face (skin color) of thedriver 300 is determined based on color information obtained from theimage data of the driver camera 150 and the part of the skin color imageis recognized as the head position of the driver. In this method, acommonly used face recognition process may be used. In this case, if anilluminator is used to emit illumination light in a visible lightwavelength band toward the imaging area (in the vicinity of the head ofthe driver 300) of the driver camera 150, a captured image with aconstant quality is obtained without being affected by an imagingenvironment (for example, difference in intensity of external light),such that it is possible to obtain a stable recognition accuracy withoutbeing affected by the imaging environment. However, in the case that anilluminator in a visible light wavelength band is used, it is necessaryto take care not to make the driver feel dazzled.

If a thermal imaging device that images far infrared rays (infraredlight) is used as the driver camera 150, a captured image (thermography)having detected far infrared rays emitted from the head of driver 300 isobtained; thus, the head position of the driver may be recognized fromthe captured image.

If an infrared camera that images near infrared rays (infrared light) isused as the driver camera 150, an infrared image having imaged the headof the driver 300 can be obtained without being affected by externaldisturbance light in the visible light wavelength band; thus, the headposition of the driver can be recognized. In this case, if anilluminator is used to emit near infrared light toward the imaging area(vicinity of the head of the driver 300) of the driver camera 150 isused, a captured image (infrared image) with a constant quality can beobtained without being largely affected by an imaging environment (forexample, difference in intensity of external light). Accordingly, astable recognition accuracy can be obtained without being largelyaffected by the imaging environment. In particular, in the configurationin which an infrared camera and an infrared illuminator are both used,since infrared light invisible to a driver is emitted to the driver, thedriver does not feel dazzled. This configuration is more beneficial inthis point than the configuration in which a camera to image in avisible light wavelength band and the visible light illuminator are bothused.

The head position of the driver 300 may be detected by using detectionresults of various sensors installed in a driver's seat of the vehicle301. For example, as disclosed in JP-2005-29040-A or the like, the headposition of the driver 300 is detected by, for example, estimating theposition of the head of the driver 300 by using one or more of thefollowing sensors: a distance sensor that detects an anteroposteriorposition of the driver's seat; an angle sensor that detects an angle ofthe seat back; a pressure sensor that detects a pressing force of thedriver against a seating surface and a seat back of the seat; and apressure sensor that detects a pressing force of the head of the driveragainst a headrest of the seat. For example, as disclosed inJP-2006-218083-A and the like, the head position of the driver 300 isdetected by using a contact sensor that detects that the head of thedriver comes into contact with the headrest of the seat and acapacitance sensor that detects in a noncontact manner that the head ofthe driver comes close to the headrest of the seat.

FIG. 8 is a schematic diagram illustrating a method of processing avirtual image G with a depth perception that is created by a motionparallax, according to the present embodiment.

When the head of the driver 300 moves by the amount “Dd” as illustratedin FIG. 8, the position at which an object Oa with a short distance Lafrom the driver 300 is visually recognized moves by the amount “Da”, andthe position at which an object Ob with a long distance Lb from thedriver 300 is visually recognized moves by the amount “Db” that issmaller than “Da”. Moreover, the position at which an object Oc with aneven longer distance Lc from the driver 300 is visually recognized movesby the amount “Dc” that is even smaller than “Db”. Due to the differencein the amounts of movement “Da”, “Db”, and “Dc” of the positions atwhich the objects Oa, Ob, and Oc are visually recognized, the driver 300can perceive that the object Oa, the object Ob, and the object Oc existwith the distance La, distance Lb, and distance Lc, respectively, awayfrom the driver 300.

In the present embodiment, the virtual image G is displayed with thedistance of 5 m away from the driver 300, and any of the images on thevirtual image G is displayed with the distance of 5 m away from thedriver 300. In the present embodiment, a plurality of images on thevirtual image G are modified using the motion parallax as describedabove such that the images are perceived by the driver 300 as if theimages are displayed with varying distances.

More specifically, the image controller 250 recognizes the position ofthe head of the driver 300 at prescribed time intervals based on thebrightness image data of the images captured by the driver camera 150.In this embodiment, the prescribed time interval corresponds to oneimage capturing frame. Then, the image controller 250 calculates thedriver's head movement amount Dd that indicates the amount where thehead of driver 300 has moved during the prescribed time intervals. Inthis case, the position at which the virtual image G is visuallyrecognized with the distance of 5 m moves by the amount “Da”.

In the present embodiment, the positions of the images that aredisplayed in the lower display area B are fixed in the display area 700.Accordingly, the position at which the images displayed in the lowerdisplay area B are visually recognized moves by the amount “Da”, whichis the same as the amount in which the virtual image G moves. As aresult, the driver 300 perceives the images displayed in the lowerdisplay area B with the distance La (5 m).

Meanwhile, the image controller 250 performs, depending on thecalculated driver's head movement amount Dd, the display control (motionparallax control) in which the lane indicator image 711 and thefollowing-distance presenting image 712 of the image parts displayed onthe upper display area A of the display area 700 of the virtual image Gis moved in the display area 700 in the direction opposite to atraveling direction of the head of the driver by a distance Da-Db. Withthis motion parallax control, regarding the lane indicator image 711 andthe following-distance presenting image 712 displayed in the upperdisplay area A, the positions at which the lane indicator image 711 andthe following-distance presenting image 712 are visually recognized fromthe driver 300 are moved by the movement amount Db. As a result, thedriver 300 perceives the lane indicator image 711 and thefollowing-distance presenting image 712 displayed at the distance Lb.

In a similar way, the image controller 250 performs the display control(motion parallax control) in which the path indicator image 721, theremaining distance indicator image 722, and the intersection or the likename indicator image 723 of the image parts displayed in the upperdisplay area A of the display area 700 of the virtual image G are moveddepending on the calculated driver's head movement amount Dd in thedisplay area 700 in the direction opposite to the traveling direction ofthe head of the driver by a distance Da-Dc. With this motion parallaxcontrol, regarding the path indicator image 721, the remaining distanceindicator image 722, and the intersection or the like name indicatorimage 723 of the image parts displayed in the upper display area A, thepositions at which the path indicator image 721, the remaining distanceindicator image 722, and the intersection or the like name indicatorimage 723 are visually recognized from the driver 300 are moved by themovement amount Dc. As a result, the driver 300 perceived the pathindicator image 721, the remaining distance indicator image 722, and theintersection or the like name indicator image 723 of the image partdisplayed at the distance Lc.

As describe above, by the motion parallax control in which the virtualimage G is projected while the movement amounts Db and Dc of the viewpositions of the image parts displayed in the upper display area A arebeing controlled depending on the driver's head movement amount Dd;thus, the driver 300 perceives such that the lane indicator image 711and the following-distance presenting image 712 are displayed at aposition more distant than the image parts (the road-name display image701, the speed limit display image 702, the no-passing zone displayimage 703, and the like) in the lower display area B and such that thecourse-change-operation instruction images 721, 722, and 723 aredisplayed at the more distant position. In this manner, it is possibleto make the driver 300 perceive as if the image parts on the virtualimage G displayed at the same distance were displayed differentdistances, such that the depth perception of the virtual image G can becreated.

Next, the display control will be described in which the perceptiondistance of the image parts displayed in the upper display area A of thedisplay area 700 of the virtual image G is changed depending on thespeed of the vehicle 301.

In the case that a motion parallax is used to make the distance to theimage displayed by the virtual image G projected from the on-vehicle HUD200 be perceived to be at the distance different from the distance tothe virtual image G, the perception distance is kept constant and is notchanged. However, as a result of a study of the inventor of the presentinvention, it has been revealed that it is useful in many aspects tochange the perception distance of the image, depending on movementinformation such as the speed and the acceleration of the vehicle 301 orposition information such as GPS information of the vehicle 301.

For example, in order to quickly and surely provide information to thedriver during driving 300, it is effective to display the for-driverinformation image indicating the information at a position close to anobservation area that the driver 300 is observing. Examples of thereason include that the driver 300 observing the observation area caneasily notice the for-driver information image and that, since the focallength of the driver 300 focusing on the vicinity of the observationarea is close, the for-driver information image can be easily focused onand be quickly visually recognized. However, the driver 300 generallytends to observe a more distant point as the speed of the vehicle 301 ishigher. Therefore, the distance of the observation area of the driver300 can change depending on the speed of the vehicle 301. For thisreason, if the perception distance of the for-driver information imageis constant, the for-driver information cannot be quickly and surelyprovided to the driver 300, depending on the speed of the vehicle 301.In such a case, if a display control is performed in which theperception distance of the for-driver information image is set longer asthe speed of the vehicle is higher, it is possible to quickly and surelyprovide the for-driver information to the driver 300 even when the speedof the vehicle changes.

To the contrary, since the driver 300 tends to observe a distant pointwhen the speed of the vehicle 301 is high, the driver 300 tends toincrease the speed of the vehicle 301 if the observation point of thedriver 300 is moved to a more distant point, the driver 300 tends todecrease the speed of the vehicle 301 if the observation point of thedriver 300 is moved to a closer point. Meanwhile, when the perceptiondistance of the for-driver information image changes, the driver 300often change the distance (focal length) of the observation point so asto follow the for-driver information image. Thus, it is possible toprompt the driver to increase or decrease the speed by changing theperception distance of the for-driver information image. By using thisfact, for example, if the display control is performed such that theperception distance of the for-driver information image is increased toprompt the driver 300 to increase the speed of the vehicle 301 when thevehicle 301 is reaching a point like a sag on a highway at whichvehicles reduce their speeds to create a congestion, it can ease thecongestion. For example, if the display control is performed such thatthe perception distance of the for-driver information image is decreasedto prompt the driver 300 to reduce the speed of the vehicle 301 when thevehicle 301 is running on a gentle downslope or the like and when thespeed of the vehicle 301 is increased before the driver 300 notices it,it can contribute the reduction of traffic accidents.

Next, an example of the display control of the present embodiment(hereinafter, the present example is referred to as a “first displaycontrol example”) will be described.

In the present first display control example, in order to quickly andsurely provide the for-driver information to the driver 300 even whenthe speed of the vehicle 301 is changed, the display control of thefor-driver information is performed such that the perception distance ofthe for-driver information is set longer as the speed of the vehicle ishigher and such that the perception distance of the for-driverinformation is set closer as the speed of the vehicle is lower. Notethat, in the following description, a description is given on thefollowing-distance presenting image 712 as an example of the for-driverinformation.

FIG. 9 is a flowchart illustrating operation of controlling display ofthe following-distance presenting image 712 in the present first displaycontrol example.

FIG. 10 is a display example of the following-distance presenting image712 when the speed of the vehicle 301 is low.

FIG. 11 is a display example of the following-distance presenting image712 when the speed of the vehicle 301 is high.

FIG. 12 is an explanatory diagram illustrating the difference in theperception distance of the following-distance presenting image 712between the display example illustrated in FIG. 10 and the displayexample illustrated in FIG. 11.

In the present first display control example, after the image controller250 obtains the vehicle-speed information of the vehicle 301 byobtaining CAN information from the sensor device 500 (step S1), theimage controller 250 determines whether the information satisfies apredetermined high-speed running condition or not, based on thevehicle-speed information of the vehicle 301 (step S2). A condition isappropriately set as the predetermined high-speed running condition,with which condition it can be determined that the vehicle speed is sohigh that the driver 300 observes a distant observation area E2.Examples of the condition include a condition that the vehicle speed isgreater than a predetermined threshold and a condition that the vehiclespeed is kept greater than a predetermined threshold for more than aspecified time.

If the predetermined high-speed running condition is satisfied (step S2:Yes), the image controller 250 determines that the driver 300 isobserving the distant observation area E2, and the image controller 250performs the display control such that the perception distance, of thefollowing-distance presenting image 712, due to motion parallax is setto the long distance Lc as illustrated in FIG. 11 and FIG. 12 (steps S3and S6). Specifically, the display control (motion parallax control) isperformed such that the movement amount, of the position at which thefollowing-distance presenting image 712 displayed in the upper displayarea A of the virtual image G is visually recognized, depending on thedriver's head movement amount Dd calculated based on the brightnessimage data of the captured image captured by the driver camera 150 isthe movement amount Dc corresponding to the perception distance Lc. Withthis operation, the following-distance presenting image 712 isdisplayed, as illustrated in FIG. 11 and FIG. 12, at a position close tothe observation area E2 that the driver 300 is observing and at theperception distance close to the distance to the observation area E2,and as a result, the following-distance information (for-driverinformation) can be quickly and surely provided to the driver duringdriving 300.

To the contrary, if the predetermined high-speed running condition isnot satisfied (step S2: No), the image controller 250 determines basedon the vehicle-speed information of the vehicle 301 whether thepredetermined low-speed running condition is satisfied (step S4) or not.A condition is appropriately set as a predetermined low-speed runningcondition, with which condition it can be determined that the vehiclespeed is so low that the driver 300 observes the close observation areaE1, Examples of the condition include a condition that the vehicle speedis lower than a predetermined threshold (the threshold is set at leastequal to or lower than the value of the threshold of the abovehigh-speed running condition) and a condition that the vehicle speed iskept equal to or lower than the predetermined threshold for more than aspecified time.

If the predetermined low-speed running condition is satisfied (step S4:Yes), the image controller 250 determines that the driver 300 isobserving the close observation area E1, and the image controller 250performs the display control such that the perception distance, of thefollowing-distance presenting image 712, due to motion parallax is theclose distance Lb as illustrated in FIG. 10 and FIG. 12 (steps S5 andS6). Specifically, the display control (motion parallax control) isperformed such that the movement amount of the position, at which thefollowing-distance presenting image 712 displayed in the upper displayarea A of the virtual image G is visually recognized and which dependson the driver's head movement amount Dd calculated based on thebrightness image data of the captured image captured by the drivercamera 150, is the movement amount Db corresponding to the perceptiondistance Lb. With this operation, the following-distance presentingimage 712 is displayed, as illustrated in FIG. 10 and FIG. 12, at aposition close to the observation area E1 that the driver 300 isobserving and at the perception distance close to the distance to theobservation area E1, and as a result, the following-distance information(for-driver information) can be quickly and surely provided to thedriver during driving 300.

Here, in the present first display control example, when the perceptiondistance of the following-distance presenting image 712 is switchedbetween the close distance Lb illustrated in FIG. 10 and the distantdistance Lc illustrated in FIG. 11, the time required to switch is setto one second or longer. That is, for example, in the case that theperception distance is switched from the close distance Lb illustratedin FIG. 10 to the distant distance Lc illustrated in FIG. 11, thedisplay control is performed to change the perception distance so slowlythat it takes one second or longer for the perception distance of thefollowing-distance presenting image 712 becomes from Lb to Lc. If thetime is less than one second, the driver perceives as if thefollowing-distance presenting image 712 moved instantaneously from theposition of the perception distance Lb to the position of the perceptiondistance Lc, and a visual stimulus is unnecessarily given to the driverduring driving. In order to avoid such a visual stimulus, the time takento switch the perception distances is preferably one second or longer.

As described above, with the present first display control example, ifthe speed of the vehicle 301 is high, the observation area E2 of thedriver 300 becomes more distant, and the perception distance Lc of thefollowing-distance presenting image 712 becomes longer, and if the speedof the vehicle 301 is low, the perception distance Lc of thefollowing-distance presenting image 712 becomes shorter as theobservation area E1 of the driver 300 becomes closer. As a result, evenif the distance of the observation area that the driver 300 observeschanges along with the change in the speed of the vehicle 301, thefollowing-distance presenting image 712 can be displayed in the vicinityof the observation area, and the following-distance information can bequickly and surely provided to the driver 300.

Note that, although the present first display control example is anexample in which the perception distance of the following-distancepresenting image 712 is changed in two steps, the perception distance ofthe following-distance presenting image 712 may be changed in threesteps, depending on the speed of the vehicle 301. In particular, in anaspect in which the display control is performed such that theperception distance of the following-distance presenting image 712 ischanged continuously depending on the speed of the vehicle 301, even ifthe distance of the observation area that the driver 300 observeschanges along with the speed of the vehicle 301, the following-distancepresenting image 712 can be displayed in the vicinity of the observationarea. Accordingly, the following-distance information can be quickly andsurely provided to the driver 300.

Although the present first display control example is an example inwhich the perception distance of the following-distance presenting image712 is changed depending on the speed of the vehicle 301, a similareffect can be achieved by changing the perception distance of thefollowing-distance presenting image 712, depending on the positioninformation of the vehicle 301.

Specifically, for example, the display control is performed such that ifit is determined, based on the route navigation information input fromthe vehicle navigation device 400, that the vehicle 301 is running on ahighway or the like on which vehicle should run at a high speed, theperception distance Lc of the following-distance presenting image 712 isset longer as illustrated in FIG. 11, and if it is determined that thevehicle 301 is running on other roads (urban roads on which vehicles areto run generally at a low speed), the perception distance Lb of thefollowing-distance presenting image 712 is set shorter as illustrated inFIG. 10.

However, if determination is made depending only on the positioninformation, the display control can be performed such that theperception distance of the following-distance presenting image 712 isset longer even when the vehicle is running actually at a low speed dueto a congestion on a highway or the like; thus, the advantage that thefollowing-distance information is quickly and surely provided cannot besufficiently provided. If determination is made depending only on thevehicle-speed information, the perception distance of thefollowing-distance presenting image 712 may be frequently switched inthe situation that the vehicle speed is frequently increased anddecreased near the threshold, and the information cannot be quickly andsurely provided to the driver against the expectation. Therefore, it iseffective to change the perception distance of the following-distancepresenting image 712 by using both of the position information and thevehicle-speed information.

Next, another example of the display control of the present embodiment(hereinafter, the present example is referred to as a “second displaycontrol example”) will be described.

In the present second display control example, the display control isperformed such that the perception distance of the following-distancepresenting image 712 is set longer when the vehicle 301 is reaching acongestion generation position such as a sag on a highway on whichvehicles reduce their speeds to create a congestion.

FIG. 13 is a flowchart illustrating a flow of a display control of thefollowing-distance presenting image 712 in the present second displaycontrol example.

FIG. 14A is a display example of the normal following-distancepresenting image 712 when the vehicle 301 is running on a highway, andFIG. 14B is a display example of the following-distance presenting image712 when the vehicle is passing through a sag (congestion generationposition) on a highway.

In the present second display control example, the image controller 250obtains the route navigation information (the position information ofthe vehicle 301) input from the vehicle navigation device 400 (stepS11), and the image controller 250 determines based on the routenavigation information whether a predetermined slowdown congestioncondition (slowdown warning condition) is satisfied (step S12) or not.Examples of the predetermined slowdown congestion condition includes,for example, a condition that a current position of the vehicle 301 isat a sag on a highway, at which a congestion is likely to be generatedby speed reduction of passing vehicles.

If the predetermined slowdown congestion condition is satisfied (stepS12: Yes), the image controller 250 performs the display control, inorder to prevent or reduce reduction in the vehicle speed or to promptincrease in the vehicle speed, such that the perception distance, of thefollowing-distance presenting image 712, due to motion parallax is setat the distance in which a predetermined distance is added to thecurrently set perception distance. For example, when the vehicle 301 isrunning on a highway, the display control is performed such that theperception distance, of the following-distance presenting image 712, dueto motion parallax is set at the distant distance Lc illustrated in FIG.14A in the same manner as in the above first display control example. Inthis situation, if the predetermined slowdown congestion condition issatisfied (step S12: Yes), the display control is performed such thatthe perception distance, of the following-distance presenting image 712,due to motion parallax is changed from Lc to Lc+. With this, the driver300 changes the distance of recognition point (focal length) such thatthe perception distance for-driver image that has changed from Lc toLc+, to increase the speed of the vehicle 301.

With the present second display control example, in the case that thevehicle 301 is reaching a congestion generation position such as a sagor the like on a highway, at which a congestion is likely to begenerated due to speed reduction of passing vehicles, the predeterminedslowdown congestion condition is satisfied, and then a display controlis performed in which the perception distance of the following-distancepresenting image 712 is set longer. This operation prompts the driver300 to increase the speed of the vehicle 301, and reduction in the speedof the vehicle 301 is thus prevented or reduced or the speed of thevehicle 301 is thus increased; therefore, the generation of congestionat the congestion generation position is prevented or reduced, orelimination of an existing congestion at the congestion generationposition is accelerated.

Note that the predetermined slowdown congestion condition is notsatisfied any longer (step S12: No), the display control is performedwith the perception distance, of the following-distance presenting image712, due to motion parallax being the previous perception distance (stepS14).

Also in the present second display control example, when the perceptiondistance of the following-distance presenting image 712 is switched, thetime required to switch the perception distances is preferably onesecond or longer in the same manner as in the first display controlexample.

Note that, contrary to the present second display control example, it ispossible to perform the display control such that the perceptiondistance of the following-distance presenting image 712 is set closer tolead the observation area of the driver to a closer position, therebyprompting the driver 300 to reduce the acceleration of the vehicle 301or to reduce the speed of the vehicle. For example, if such a displaycontrol is performed in the case that the vehicle 301 is running at avehicle acceleration point such as a gentle downslope, at which thevehicle speed is increased before the driver 300 notices it, it is alsopossible to prompt the driver 300 to reduce the acceleration of thevehicle 301 or to reduce the speed of the vehicle and thus to contributeto prevention or reduction of traffic accidents due to excessive speed.Such a display control is achieved by the image controller 250recognizing, based on the route navigation information (the positioninformation of the vehicle 301) input from the vehicle navigation device400, that the vehicle 301 is passing through a vehicle accelerationpoint as described above.

In the present second display control example, an example is describedin which the perception distance of the following-distance presentingimage 712 is changed depending on the position information of thevehicle 301; however, a similar effect can be achieved by changing theperception distance of the following-distance presenting image 712,depending on the movement information such as the speed of the vehicle301. Specifically, for example, in the case that the display control isperformed, based on the vehicle-speed information obtained from thesensor device 500, such that the perception distance of thefollowing-distance presenting image 712 is increased when the speed ofthe vehicle becomes lower than a prescribed speed and that the speed ofthe vehicle 301 is reduced at a congestion generation position such as asag on a highway at which a congestion is likely to be generated due tospeed reduction of passing vehicles, it is possible to prompt the driver300 to increase the speed of the vehicle 301, thereby easing thecongestion.

Next, still another example of the display control of the presentembodiment (hereinafter, the present example is referred to as a “thirddisplay control example”) will be described.

In the present embodiment, the following-distance presenting image 712,whose perception distance is changed based on the vehicle-speedinformation of the vehicle 301 (movement information), the routenavigation information (position information), and the like, isdisplayed to be superimposed on the actual road surface (travelingsurface) ahead of the vehicle. In the case that the perception distanceof the for-driver information image virtually disposed on a road surfaceis increased, if the display position of the for-driver informationimage is moved further upward, it makes the driver 300 easily recognizethat the distance of the for-driver information image becomes longeralong the actual road surface. Therefore, also in the above variousdisplay controls, when the perception distance of the following-distancepresenting image 712 is increased, not only the movement amount of theposition at which the following-distance presenting image 712 isvisually recognized is changed depending on the driver's head movementamount Dd, but also the position at which the following-distancepresenting image 712 is visually recognized is set to a higher position.

Here, in the case that the height of the position at which thefor-driver information image is visually recognized is changed, therange in which the height can be changed is limited to the display area700 of the virtual image G of the on-vehicle HUD 200. Because theposition of the display area 700 of the virtual image G is fixed, inorder to change the height of the position at which the for-driverinformation image is visually recognized, the relative position of thefor-driver information image with respect to the display area 700 ischanged. The length of the display area 700 in the height direction (theangle of view in the vertical direction) is difficult to increase inmany cases from the point of view of downsizing of the on-vehicle HUD200 or the like. Therefore, when the range of the perception distance ofthe for-driver information image is distant, it is impossible in somecases to change the height of the for-driver information image inaccordance with the change in the perception distance. To the contrary,if the for-driver information image is made smaller, it is possible tosecure the range in which the height of the for-driver information imageis changed; however, a problem occurs in which visibility of thefor-driver information image is accordingly lowered.

To address this issue, in the present third display control example,when the perception distance of the for-driver information image ischanged, a control is performed in which the position of the displayarea 700 instead of changing the relative position of the for-driverinformation image in the display area 700, or in addition to changingthe relative position.

FIG. 15 is a flowchart illustrating operation of controlling display ofthe following-distance presenting image 712 in the present third displaycontrol example.

FIG. 16A is a display example of the following-distance presenting image712 when the speed of the vehicle 301 is low. FIG. 16B is a displayexample of the following-distance presenting image 712 when the speed ofthe vehicle 301 is high.

In the present third display control example, in the same manner as inthe above first display control example, when the image controller 250obtains the vehicle-speed information of the vehicle 301 (step S21), theimage controller 250 determines, based on the vehicle-speed informationof the vehicle 301, whether the predetermined high-speed runningcondition is satisfied (step S22) or not. Then, if the predeterminedhigh-speed running condition is satisfied (step S22: Yes), the displaycontrol is performed such that the perception distance, of thefollowing-distance presenting image 712, due to motion parallax is setto the distant distance Lc as illustrated in FIG. 16B (steps S23 andS26). At this time, in the present third display control example, notonly the display control (motion parallax control) is performed suchthat the movement amount, of the position at which thefollowing-distance presenting image 712 displayed in the upper displayarea A of the virtual image G is visually recognized, depending on thedriver's head movement amount Dd calculated based on the brightnessimage data of the captured image captured by the driver camera 150, isthe movement amount Dc corresponding to the perception distance Lc, butalso a display control (display area control) is performed in which theposition of the display area 700 is moved upward.

Examples of the method of the display area control for moving theposition of the display area 700 include, for example, a method in whicha reflection surface angle of the projector mirror 211 provided on theon-vehicle HUD 200 is changed. Specifically, the projector mirror 211 isrotatably moved about a rotation axis parallel to a reflection surfaceof the projector mirror 211 to change the reflection surface angle ofthe projector mirror 211 so that the projected display area 700 of thevirtual image G is moved upward (in the direction of arrow C in FIGS.16A and 16B). The present third display control example employs thismethod, and a drive motor of the projector mirror 211 is controlledbased on the set perception distance of the following-distancepresenting image 712 so that the reflection surface angle of theprojector mirror 211 is changed to move the position of the display area700 upward. As a result, the position at which the following-distancepresenting image 712 is visually recognized can be moved upward, asillustrated in FIG. 16B, to the position at which the position of thedisplay area 700 cannot be displayed if the display is kept asillustrated in FIG. 16A. Thus, even in the case that thefollowing-distance presenting image 712 cannot be displayed at theposition close to the observation area E2, which the driver 300 isobserving, when the position of the display area 700 is kept asillustrated in FIG. 16A, the following-distance presenting image 712 canbe displayed at the position close to the observation area E2 so thatthe following-distance information (for-driver information) can bequickly and surely provided to the driver during driving 300.

If the predetermined low-speed running condition is satisfied (step S24:Yes), the display control is performed such that the perceptiondistance, of the following-distance presenting image 712, due to motionparallax is set to the close distance Lb as illustrated in FIG. 16A(steps S25 and S26). Also in this case, in the present third displaycontrol example, not only the motion parallax control is performed, butalso the display area control is performed to move the position of thedisplay area 700 upward. Specifically, the drive motor of the projectormirror 211 is controlled, based on the set perception distance of thefollowing-distance presenting image 712, to change the reflectionsurface angle of the projector mirror 211 so that the position of thedisplay area 700 is moved downward. As a result, the position at whichthe following-distance presenting image 712 is visually recognized canbe moved, as illustrated in FIG. 16A, downward to the position at whichthe position of the display area 700 cannot be displayed if the displayis kept as illustrated in FIG. 16B. Thus, even in the case that thefollowing-distance presenting image 712 cannot be displayed at theposition close to the observation area E1 when the position of thedisplay area 700 is kept as illustrated in FIG. 16B, thefollowing-distance presenting image 712 can be displayed at the positionclose to the observation area E1 so that the following-distanceinformation (for-driver information) can be quickly and surely providedto the driver during driving 300.

Note that, in the above embodiment, the information of the vehicle 301used to change the perception distance of the following-distancepresenting image 712 is the vehicle-speed information and the positioninformation of the speed of the vehicle 301; however, the perceptiondistance of the for-driver information image may be changed depending onother information such as the acceleration information (movementinformation) of the vehicle 301 if it provides an advantageous effect.

In the present embodiment, the HUD 230 serving as an image-lightprojection device is used as the image display, which image-lightprojection device projects the image light to the light transmissionmember so as to display the for-driver information image in thepredetermined display area 700 that the driver 300 visually recognizesahead in a mobile object traveling direction via the light transmissionmember such as the windshield 302; however, the image display may be adevice that displays the for-driver information image on the displaydevice such as a liquid crystal display and an organic EL displaydisposed on the dashboard or the like near the driver's seat.

Note that, also in the above information provision device, anabnormality may occur in some cases in the detection result of theviewpoint detector due to various causes such as erroneous detection ofthe viewpoint detector caused by a failure of the viewpoint detector orthe imaging environment. If an abnormality occurs in the detectionresult of the viewpoint detector, the display position of an image canabnormally change, for example; thus, not only the visibility of theimage can become low, but also unnecessary stress can be given to thedriver.

To address this issue, it is preferable to provide an informationprovision device that can secure visibility of the for-driverinformation image and reduce unnecessary stress that can be given to thedriver, even if an abnormality occurs in the detection result of theviewpoint detector.

Referring to FIGS. 17 to 19, a description will be given to anabnormality handling process that deals with an abnormality occurring ina recognition process, of the head position of the driver 300, based onthe captured image of the driver camera 150.

In the present embodiment, the sense of distance and the depthperception of the virtual image G are created as described above byusing the motion parallax by projecting the virtual image G whilecontrolling, depending on the driver's head movement amount Dd, themovement amounts Db and Dc of the positions at which the image parts711, 712, 721, 722, and 723 displayed in the upper display area A arevisually recognized. In this process, if there is an abnormality in therecognition result of the driver's head movement amount Dd, which iscalculated from the result of recognition, of the head position of thedriver 300, based on the brightness image data from the driver camera150, it is impossible to appropriately control the movement amounts Dband Dc of the positions at which the image parts 711, 712, 721, 722, and723 are visually recognized.

For example, if the head of the driver 300 is irradiated with a strongsunlight, the received light amounts of the light receiving elements onthe image sensor of the driver camera 150 are saturated, and thebrightness image data with so-called halation are imaged in some cases.Such brightness image data include many pixels having the maximum value(white), and there is no brightness difference. In such case, theresometimes occurs incorrect recognition of the head position of thedriver 300, or the head position of the driver 300 is not alwaysrecognized. Such an incorrect recognition or unrecognizability isdifficult to quickly avoid even if an automatic exposure controloperates on the driver camera 150.

When the incorrect recognition of the head position occurs, the headposition is sometimes recognized to be at a different position that isdistant from the head position at which the head position is recognizedimmediately before and to which the head position cannot move in aperiod of time corresponding to the sampling period (the time periodbetween imaging frames if the head position is recognized at everyimaging frame) with which the brightness image data are obtained torecognize the head position. Alternatively, if the incorrect recognitionof the head position occurs, the head position is recognized in somecases as if the head position expected from the continuously obtainedrecognition results of the head positions moved in a normallyunconceivable way. If the movement amounts Db and Dc of the positions atwhich the image parts 711, 712, 721, 722, and 723 displayed in the upperdisplay area A are visually recognized are controlled depending on thedriver's head movement amount Dd calculated based on the recognitionresult of the head position that is incorrectly recognized as describedabove, the sense of distance and the depth perception due to the motionparallax cannot be obtained any longer. In addition to that, the displaypositions of the image parts 711, 712, 721, 722, and 723 are abnormallychanged, and as a result, the visibility of the image parts is lowered,or unnecessary stress is given to the driver during driving 300.

In the case that unrecognizability of the head position occurs, theimage parts 711, 712, 721, 722, and 723 are displayed abnormally; thus,the visibility of the image parts can be lowered, or unnecessary stresscan be given to the driver during driving 300.

To address these issues, in the present embodiment, in the case that anabnormality such as incorrect recognition and unrecognizability occursto the recognition result, of the head position, based on the capturedimage of the driver camera 150, the movement amounts Db and Dc of thepositions at which the image parts 711, 712, 721, 722, and 723 arevisually recognized are not controlled depending on the driver's headmovement amount Dd calculated from such recognition results, but apredetermined abnormality handling process is performed.

Hereinafter, an example of the abnormality handling process in thepresent embodiment (hereinafter, the present example is referred to as a“first abnormality handling process example”) will be described.

In the present first abnormality handling process example, anabnormality handling process is performed in which, when the recognitionresult, of the head position, based on the captured image of the drivercamera 150 satisfies a predetermined abnormal condition, the displaypositions of the image parts 711, 712, 721, 722, and 723 displayed inthe upper display area A are kept at the immediately preceding displaypositions.

FIG. 17 is a flowchart illustrating a flow of a process in the firstabnormality handling process example.

After the captured image data are input from the driver camera 150 (stepS31), the image controller 250 recognizes, as described above, the headposition of the driver 300, based on the brightness image data of thecaptured image captured by the driver camera 150 (step S32). Then, ifthe head position cannot be recognized (step S33: Yes), the imagecontroller 250 determines that the abnormal condition is satisfied andperforms the abnormality handling process in which the display positionsof the image parts 711, 712, 721, 722, and 723 displayed in the upperdisplay area A are kept at the immediately preceding display positions(step S42). With this operation, even if the head position of the driveris unrecognizable due to some causes, it is possible to avoid thesituation that the visibility of the image parts is lowered orunnecessary stress is given to the driver during driving 300 due toabnormally change in the display positions of the image parts.

If the head position is recognized (step S33: No), the image controller250 next determines whether the recognized head position is in aspecified range (step S34) or not. This operation is for extracting anabnormal recognition result that the following position is recognized asthe head position: (i) a position out of an imaging area of the drivercamera 150; or (ii) a position at which the head position of the driverduring driving 300 cannot be located, and the specified range isappropriately set in such a range that those recognition results can beextracted. If the image controller 250 determines that the recognizedhead position is out of the specified range (step S34: No), the imagecontroller 250 determines that the abnormal condition is satisfied andperforms the abnormality handling process in which the display positionsof the image parts 711, 712, 721, 722, and 723 displayed in the upperdisplay area A are kept at the immediately preceding display positions(step S12). With this operation, even if an abnormal recognition resultof the head position of the driver occurs due to some causes, it ispossible to avoid the visibility of the image parts from being loweredand unnecessary stress given to the driver during driving 300.

If the image controller 250 determines that the recognized head positionis within the specified range (step S34: Yes), the image controller 250reads out from the RAM 252 the recognition result of the head positionwhen the immediately preceding motion parallax control was performed,and the image controller 250 calculates the distance between theread-out immediately preceding head position and the currentlyrecognized head position as the driver's head movement amount Dd that isthe distance the head of the driver travels from the time when theimmediately preceding motion parallax control is performed and to thetime of the current motion parallax control (step S35). Then, the imagecontroller 250 determines whether the calculated driver's head movementamount Dd is equal to or less than a predetermined threshold (step S36)or not. This step is for extracting the abnormal recognition result inwhich a position that can be obtained only when the head is moving at anunusually high speed has been recognized as the head position, and thepredetermined threshold is appropriately set so that such an abnormalrecognition result can be extracted.

Then, if the image controller 250 determines that the calculateddriver's head movement amount Dd is greater than the predeterminedthreshold (step S36: No), the image controller 250 determines that theabnormal condition is satisfied, and the image controller 250 performsthe abnormality handling process in which the display positions of theimage parts 711, 712, 721, 722, and 723 displayed in the upper displayarea A are kept at the immediately preceding display positions (stepS42). With this operation, even if an abnormal recognition result of thehead position of the driver occurs due to some causes, it is possible toavoid the visibility of the image parts from being lowered andunnecessary stress given to the driver during driving 300.

Next, if the image controller 250 determines that the calculateddriver's head movement amount Dd is equal to or less than thepredetermined threshold (step S36: Yes), the image controller 250 usesas the motion information of the head the recognition results in apredetermined period including the current recognition result of thehead position (for example, the recognition results for the latest 10frames) (step S37), and it is determined whether the motion informationsatisfies the abnormal motion condition (step S38) or not. Thisoperation is for extracting a motion of the head recognized from therecognized head positions as an abnormal recognition result of the headposition if the motion exhibits a movement that cannot be exhibited as anormal behavior. Examples of such an abnormal motion include, forexample, an motion in which the head position reciprocally moves at avery short cycle (for example, a cycle corresponding to one or twoframes), and a condition is appropriately set as the abnormal motioncondition, with which condition an abnormal motion can be extracted.Note that the image controller 250 stores the recognition result of thehead positions in a predetermined period (for example, the periodcorresponding to the latest 10 frames) in the RAM 252, and theserecognition results are read out from the RAM 252 to generate the motioninformation.

Then, if the image controller 250 determines that the generated motioninformation satisfies a predetermined abnormal motion condition (stepS38: Yes), the image controller 250 determines that the abnormalcondition is satisfied, and the image control performs the abnormalityhandling process in which the display positions of the image parts 711,712, 721, 722, and 723 displayed in the upper display area A are kept atthe immediately preceding display positions (step S42). With thisoperation, even if an abnormal recognition result of the head positionof the driver occurs due to some causes, it is possible to avoid thevisibility of the image parts from being lowered and unnecessary stressgiven to the driver during driving 300.

Meanwhile, if the image controller 250 determines that the generatedmotion information does not satisfy the predetermined abnormal motioncondition (step S38: No), the image controller 250 determines that thecurrent recognition result of the head position is a normal recognitionresult, which does not satisfy any of the abnormal conditions. Then,depending on the driver's head movement amount Dd calculated in theabove step S5, the image movement amounts Db and Dc of the image parts711, 712, 721, 722, and 723 displayed in the upper display area A in thedisplay area 700 of the virtual image G are calculated (step S39), and adisplay control (motion parallax control) is performed in which theimage parts are moved corresponding to the calculated image movementamounts Db and Dc (step S40). This operation can make the driver 300visually recognize as if the image parts 711, 712, 721, 722, and 723displayed in the upper display area A were displayed at the distanceaway from the perception distance of the virtual image G. Note that thenormal recognition result of the head position is stored in the RAM 252(step S41).

With the present first abnormality handling process example, if thecurrent recognition result of the head position satisfies any one of theabove abnormal conditions, the abnormality handling process is performedinstead of the motion parallax control, in which abnormality handlingprocess the image parts 711, 712, 721, 722, and 723 displayed in theupper display area A are kept at the immediately preceding displaypositions. With this operation, even if the head position of the drivercannot be recognized or an abnormal recognition result of the headposition of the driver occurs due to some causes, it is possible toavoid the visibility of the image parts from being lowered andunnecessary stress given to the driver during driving 300.

Note that, in the case that the incorrect recognition or theunrecognizability of the head position is created in association with atemporary change in the imaging environment, for example, in the casethat the head of the driver 300 is irradiated with a strong sunlight,the recognition result of the head position will be able to obtainedafter a short time, for example, after the imaging environment recovers.In this case, in the present first abnormality handling process example,none of the abnormal conditions is satisfied any longer. The motionparallax control is performed again on the image parts 711, 712, 721,722, and 723 displayed in the upper display area A.

Next, another example of the abnormality handling process in the presentembodiment (hereinafter, the present example is referred to as a “secondabnormality handling process example”) will be described.

In the present second abnormality handling process example, if therecognition result, of the head position, based on the captured image ofthe driver camera 150 satisfies a predetermined abnormal condition, anabnormality handling process is performed in which at least part of theimage parts 711, 712, 721, 722, and 723 displayed in the upper displayarea A is undisplayed. In the description below, processes similar tothe above first abnormality handling process example are not describedagain if appropriate.

FIG. 18 is a flowchart illustrating a flow of a process in the presentsecond abnormality handling process example.

Also in the present second abnormality handling process example,similarly to the above first abnormality handling process example, ifthe current recognition result of the head position satisfies any one ofthe abnormal conditions, the abnormality handling process is performedinstead of the motion parallax control, in which abnormality handlingprocess the image parts 711, 712, 721, 722, and 723 displayed in theupper display area A are kept at the immediately preceding displaypositions (steps S31 to S42). However, in the present second abnormalityhandling process example, if the recognition result of the head positionsatisfies the abnormal condition for a period longer than a specifiedtime (step S51), an abnormality handling process immediately precedingdisplay positions is performed in which at least part of the image parts711, 712, 721, 722, and 723 is undisplayed (step S52).

At this time, an image part to be undisplayed cannot provide thefor-driver information to the driver any longer by that image part;therefore, it is preferable to undisplay the image part that gives moretrouble when the image part having no effect of motion parallax is keptdisplayed than when the image part is undisplayed and provides nofor-driver information to the driver, for example. For example, in thepresent second abnormality handling process example, thefollowing-distance presenting image 712 is undisplayed.

With the present second abnormality handling process example, in thecase that the cause of the incorrect recognition of the head position orthe unrecognizability is, for example, not a temporary one such as achange in the imaging environment but a continuous one such as a failureof the driver camera 150, it is possible to avoid a trouble caused by animage having no effect of motion parallax being displayed for long.

Note that, instead of the abnormality handling process in which theimage parts 711, 712, 721, 722, and 723 are kept at the immediatelypreceding display positions, an abnormality handling process may beperformed in which at least a part of the image parts 711, 712, 721,722, and 723 is undisplayed. That is, if the current recognition resultof the head position satisfies any of the abnormal conditions, theabnormality handling process may be performed in which at least part ofthe image parts 711, 712, 721, 722, and 723 without abnormality handlingprocess to keep at the immediately preceding display positions.

Next, still another example of the abnormality handling process in thepresent embodiment (hereinafter, the present example is referred to as a“third abnormality handling process example”) will be described.

In the present third abnormality handling process example, if therecognition result, of the head position, based on the captured image ofthe driver camera 150 satisfies a predetermined abnormal condition, anabnormality handling process is performed in which the display positionof at least part of the image parts 711, 712, 721, 722, and 723displayed in the upper display area A is changed to a predeterminedreference position.

FIG. 19 is a flowchart illustrating a flow of a process in the presentthird abnormality handling process example.

In the present third abnormality handling process example, if thecurrent recognition result of the head position satisfies any of theabnormal condition similarly to the above first abnormality handlingprocess example, an abnormality handling process is performed in whichthe display positions of the image parts 711, 712, 721, 722, and 723displayed in the upper display area A are changed to predeterminedreference positions (step S71), instead of the abnormality handlingprocess (process for keeping at the immediately preceding displaypositions) in the above first abnormality handling process example beingperformed.

Regarding the reference position, in a simple manner, for example, theposition corresponding to the most normal position of the head of thedriver sitting in the driver's seat may be previously stored in the ROM253, and this position may be used as the reference position. However,even if the driver sits on the same driver's seat, the head position ofthe driver 300 depends on an anteroposterior position of the driver'sseat, an angle of the seat back, a physical feature such as a height ofthe driver. Therefore, for example, it is possible to store in the RAM252 the position corresponding to the first, normally recognized headposition of the driver based on the captured image of the driver camera150 after the on-vehicle HUD 200 is started, and such position may beused as the reference position.

Also in the present third abnormality handling process example, in asimilar manner to the above first abnormality handling process example,even if the head position of the driver cannot be recognized or anabnormal recognition result of the head position of the driver occursdue to some causes, it is possible to avoid the visibility of the imageparts from being lowered and unnecessary stress given to the driverduring driving 300.

Note that, in the present embodiment, the HUD 230 serving as animage-light projection device is used as the image display, whichimage-light projection device projects the image light to the lighttransmission member so as to display the for-driver information image inthe predetermined display area 700 that the driver 300 visuallyrecognizes ahead in a mobile object traveling direction via the lighttransmission member such as the windshield 302; however, the imagedisplay may be a device that displays the for-driver information imageon the display device such as a liquid crystal display and an organic ELdisplay disposed on the dashboard or the like near the driver's seat.

As described above, the inventor found that, when information isprovided to the driver, it is effective to change a perception distancedepending on movement information and position information of a mobileobject that the driver is driving even if the image having the samecontent of information is displayed. In detail, if display control isperformed to change the perception distance of a for-driver informationimage depending on at least one of the movement information such asspeed and acceleration of the mobile object that the driver is drivingand the position information such as GPS (Global Positioning System)information of the mobile object, it is possible to provide at least oneadvantageous effect, for example, as described above.

In one embodiment, an information provision device such as an on-vehicleHUD 200 includes an image display such as an HUD 230 that displays afor-driver information image such as a following-distance presentingimage 712 that displays for-driver information such asfollowing-distance information that is provided to a driver 300 of amobile object such as vehicle 301. The information provision deviceincludes: an obtaining unit such as data I/F 255 that obtains at leastone of (i) movement information such as vehicle-speed information andacceleration information of the mobile object and (ii) positioninformation such as route navigation information of the mobile object;and a display controller such as the CPU (251) of the image controller250 that performs a display control in which perception distances Lb andLc, of the for-driver information image, for the driver due to motionparallax. More specifically, the display controller changes a displayposition of the for-driver information image, based on a detectionresult of the viewpoint detector (driver camera 150) indicating aviewpoint position of the driver. The display controller performs thedisplay control such that the perception distance of the for-driverinformation image for the driver due to motion parallax, changesaccording to the at least one piece of information that the obtainingunit obtains.

Accordingly, the perception distance of the for-driver informationimage, for the driver due to motion parallax, can be changed based on atleast one of the movement information and the position information ofthe mobile object.

In the above-described embodiment, in one example, the obtaining unitobtains moving-speed information such as vehicle-speed information ofthe mobile object as the movement information, and the displaycontroller performs, depending on the moving-speed information obtainedby the obtaining unit, the display control such that the perceptiondistance is more distant as a moving speed of the mobile object ishigher and such that the perception distance is shorter as the movingspeed of the mobile object is lower.

In order to quickly and surely provide information to the driver drivingthe mobile object, it is effective, as described above, to display thefor-driver information image indicating the information at a positionclose to an observation area that the driver is observing. However, thedriver generally tends to observe a more distant point as the speed ofthe mobile object is higher. Therefore, the distance of the observationarea of the driver can vary depending on the speed of the mobile object.In such a case, if the perception distance of the for-driver informationimage is constant, the for-driver information image may be away from theobservation area, depending on the speed of the mobile object.Accordingly, the for-driver information cannot be quickly and surelyprovided to the driver. With the present aspect, the perceptiondistance, of the for-driver information image, due to motion parallax ischanged such that the perception distance is longer as the speed of themobile object is higher and such that the perception distance is shorteras the speed of the mobile object is lower; thus, even if the speed ofthe mobile object changes, the for-driver information can be quickly andsurely provided to the driver.

In the above-described embodiment, in one example, the obtaining unitobtains the moving-speed information of the mobile object as themovement information, and the display controller performs the displaycontrol such that the perception distance becomes shorter when themoving-speed information obtained by the obtaining unit satisfies apredetermined speed-increase warning condition.

When the perception distance of the for-driver information image ischanged, the driver often changes the distance (focal length) of theobservation point so as to follow the for-driver information image.Because the driver tends to observe a close point when the speed of themobile object is low as described above, if the observation point of thedriver is moved closer, the driver tends to try to reduce the speed ofthe mobile object. As a result, by shortening the perception distance ofthe for-driver information image, it is possible to prompt the driver toreduce the speed. With the present aspect, if the speed of the mobileobject satisfies the predetermined speed-increase warning condition, theperception distance, of the for-driver information image, due to motionparallax becomes shorter. Thus, for example, if a condition isappropriately set as the predetermined speed-increase warning condition,with which condition it can be recognized that the speed of the mobileobject increases before the driver notices it, it is possible to promptthe driver to reduce the speed of the mobile object, therebycontributing reduction of traffic accidents due to excessive speed.

In the above-described embodiment, in one example, the obtaining unitobtains position information such as the route navigation information ofthe mobile object, and the display controller performs the displaycontrol such that the perception distance becomes shorter when theposition information obtained by the obtaining unit satisfies apredetermined speed-increase warning condition.

With the present aspect, for example, if a condition is appropriatelyset as the predetermined speed-increase warning condition, with whichcondition it can be recognized that the mobile object passes throughsuch a position that the speed of the mobile object increases before thedriver notices it, it is possible to prompt the driver, when in such asituation, to reduce the speed of the mobile object by shortening theperception distance, of the for-driver information image, due to motionparallax, thereby contributing reduction of traffic accidents due toexcessive speed.

In the above-described embodiment, in one example, the obtaining unitobtains the speed information of the mobile object as the movementinformation, and the display controller performs the display controlsuch that the perception distance becomes longer when the moving-speedinformation obtained by the obtaining unit satisfies a predeterminedslowdown warning condition.

As described above, if the perception distance of the for-driverinformation image changes, the driver often changes the distance (focallength) of the observation point so as to follow the for-driverinformation image. Then, because the driver tends to observe a distantpoint when the speed of the mobile object is high, if the observationpoint of the driver is changed to a distant position, the driver tendsto increase the speed of the mobile object. Therefore, by increasing theperception distance of the for-driver information image, it is possibleto prompt the driver to increase the speed. With the present aspect, ifthe speed of the mobile object satisfies the predetermined slowdownwarning condition, the perception distance, of the for-driverinformation image, due to motion parallax becomes longer. Thus, forexample, if a condition is appropriately set as the predeterminedslowdown warning condition, with which condition it can be recognizedthat there is a situation that the speed of the mobile object decreasesbefore the driver notices it, it is possible to prompt, when in such asituation, the driver to increase the speed of the mobile object,thereby contributing to reducing generation of congestion or reducingdelay in recovering from congestion due to speed reduction of mobileobjects.

In the above-described embodiment, in one example, the obtaining unitobtains position information of the mobile object, and the displaycontroller performs the display control such that the perceptiondistance becomes longer if the position information obtained by theobtaining unit satisfies a predetermined slowdown warning condition.

With the present aspect, for example, if a condition is appropriatelyset as the predetermined slowdown warning condition, with whichcondition it can be recognized that the mobile object passes throughsuch a position that the speed of the mobile object decreases before thedriver notices it, it is possible to prompt the driver, when in such asituation, to increase the speed of the mobile object by increasing theperception distance, of the for-driver information image, due to motionparallax, thereby contributing to reducing generation of congestion orreducing delay in recovering from congestion due to reduction in thespeed of mobile objects.

In the above-described embodiment, it takes one second or longer for thedisplay control to change the perception distance.

With this arrangement, when the perception distance, of the for-driverinformation image, due to motion parallax is changed, it is possible toprevent the driver from recognizing that the for-driver informationimage instantaneously moves from the position before changing to theposition after changing. As a result, it is possible to change theperception distance, of the for-driver information image, due to motionparallax without giving unnecessary visual stimulus to the driver duringdriving.

In the above-described embodiment, the display controller causes theimage display to display plural kinds of the for-driver informationimages (for example, the image displayed in the upper display area A andthe images displayed in the lower display area B) each of which hasdifferent perception distance from each other, and performs the displaycontrol such that the perception distance of at least one kind of imageof the plural kinds of the for-driver information images is changed.

With this operation, it is possible to change the perception distance ofonly a part of multiple kinds of the for-driver information imagesdisplayed by the image display or to differentiate the perceptiondistance of each of the plural kinds of the for-driver informationimages.

In the above-described embodiment, the image display is an image-lightprojection device that projects the image light to a light transmissionmember such as the windshield 302 so as to display the for-driverinformation image in the predetermined display area 700 that the driver300 visually recognizes, ahead in a mobile object traveling direction,via the light transmission member.

This arrangement allows the driver driving the mobile object to visuallyrecognize the for-driver information image without largely turning thedriver's eyes from the mobile object traveling direction.

In the above-described embodiment, the image display includes a displayarea moving unit such as a projector mirror 211 that moves thepredetermined display area as driven by a drive motor. In the displaycontrol, the perception distance is changed by changing the displayposition of the for-driver information image and the predetermineddisplay area, based on the detection result of the viewpoint detector.

This arrangement makes it possible to change the position, at which thefor-driver information image is visually recognized, without beinglimited by the size of the display area. This allows to change theperception distance in a wider range without making the for-driverinformation image smaller.

In the above-described embodiment, the image-light projection devicedisplays the for-driver information image with the projected image lightas a virtual image G in the predetermined display area, and the distancefrom the driver to the virtual image is equal to or greater than 5 m.

If the distance to the virtual image G is about 2 m, which is a commondistance, the eyeballs usually need to perform a convergence movement tomake the eyes focus on the virtual image G. As described above, theconvergence movement is a cause that largely affects the sense ofdistance to the viewing object and the depth perception, and if theconvergence movement is performed to focus on the virtual image G, thesense of distance (change in the perception distance) and the depthperception (difference in the perception distance) due to motionparallax cannot be effectively visually recognized.

With the present aspect, since the distance to the virtual image G isequal to or greater than 5 m, it is possible to focus on the virtualimage G almost without letting the eyeballs perform a convergencemovement. Accordingly, the sense of distance (change in perceptiondistance) or the depth perception (difference in perception distance),which are expected to be brought by motion parallax, can be perceived asdesired in absence of the convergence motion of the eyes.

In the above-described embodiment, the image-light projection devicedisplays the for-driver information image in the predetermined displayarea by making a light scanner such as an optical scanner 208two-dimensionally scan and project, onto the light transmission member,the image light emitted from a light emitter such as a light source unit220 that emits image light depending on image information of thefor-driver information image.

As described above, it is easy to display a larger virtual image G in ahigher brightness than by using a liquid crystal display (LCD), a vacuumfluorescent display (VFD), or the like. With the present aspect, sinceimage light is not emitted from light emitter to a non-image part in thevirtual image G, it is possible to completely eliminate light on thenon-image part. Thus, it is possible to avoid the visibility of thescenery, through the non-image part, ahead of the mobile object frombeing lowered by the light emitted from the light emitter, and thevisibility of the scenery ahead is high.

In one embodiment, an information providing method is provided, whichcauses an image display to display a for-driver information image to thedriver of a mobile object. The method includes: obtaining at least onepiece of information of movement information of the mobile object andposition information of the mobile object; detecting a viewpointposition of the driver; and performing a display control to change aperception distance, of the for-driver information image, for the driverdue to motion parallax, by changing a display position of the for-driverinformation image, depending on a detection result in the step ofdetecting a viewpoint position. In the step of performing a displaycontrol, the display control is performed such that the perceptiondistance, of the for-driver information image, for the driver due tomotion parallax changes depending on the at least one piece ofinformation obtained in the step of obtaining at least one piece ofinformation.

With the present aspect, it is possible to change the perceptiondistance, of the for-driver information image, for the driver due tomotion parallax, depending on the movement information and the positioninformation of the mobile object.

In another embodiment, a control program for causing an image display todisplay a for-driver information image to a driver of a mobile object isprovided, which performs the above-described method.

In another embodiment, an information provision device such as anon-vehicle HUD 200 includes an image display such as an HUD 230 thatdisplays for-driver information image such as the lane indicator image711, the following-distance presenting image 712, the path indicatorimage 721, the remaining distance indicator image 722, and theintersection or the like name indicator image 723 that display variouskinds of for-driver information to be provided to a driver 300 of amobile object such as a vehicle 301. The information provision deviceincludes: a viewpoint detector such as a driver camera 150 that detectsa viewpoint position of the driver; and a display controller such as theprocessor of the image controller 250 that performs a display control inwhich a perception distance, of the for-driver information image, forthe driver due to motion parallax is changed by changing a displayposition of the for-driver information image, depending on the detectionresult of the viewpoint detector. The display controller performs,instead of the display control, a predetermined abnormality handlingprocess if the detection result of the viewpoint detector satisfies thepredetermined abnormal condition.

Accordingly, if an abnormality satisfying a predetermined abnormalcondition occurs in a detection result by the viewpoint detector, thedisplay control is not performed based on the abnormal detection result.This prevents a situation from occurring in which the display positionof the for-driver information image is abnormally changed. Instead, anabnormality handling process having an appropriate content is performedwhen an abnormality occurs in the detection result by the viewpointdetector. This results in securing the visibility, of the for-driverinformation image, for the driver while achieving reduction inunnecessary stress that can be given to the driver.

In the above-described embodiment, in one example, the predeterminedabnormal condition includes a condition that the viewpoint detectorcannot detect the viewpoint position of the driver.

With this arrangement, even if the viewpoint position of the drivercannot be detected, a situation does not occur in which the displayposition of the for-driver information image abnormally changes, and anabnormality handling process having an appropriate content is performed.This results in securing the visibility, of the for-driver informationimage, for the driver while achieving reduction in unnecessary stressthat can be given to the driver.

In the above-described embodiment, the predetermined abnormal conditionincludes a condition that the viewpoint position of the driver detectedby the viewpoint detector is a viewpoint position out of a predeterminedviewpoint-moving range such as a specified range with respect to aviewpoint position having been detected in the past.

With this arrangement, even if the viewpoint detector detects, as aviewpoint position, a position that is out of a detection range of theviewpoint detector or at which the viewpoint of the driver duringdriving cannot normally be located, a situation does not occur in whichthe display position of the for-driver information image changesabnormally, and an abnormality handling process having an appropriatecontent is performed. This results in securing the visibility, of thefor-driver information image, for the driver while achieving reductionin unnecessary stress that can be given to the driver.

In this embodiment, in one example, the predetermined abnormal conditionincludes a condition that multiple viewpoint positions detected by theviewpoint detector in a predetermined period satisfy a predeterminedviewpoint-abnormally-moving condition.

With this arrangement, even if the viewpoint detector detects aviewpoint position that indicates that the motion of the head of thedriver exhibits a motion that cannot normally be exhibited, a situationdoes not occur in which the display position of the for-driverinformation image changes abnormally, and an abnormality handlingprocess having an appropriate content is performed. This results insecuring the visibility, of the for-driver information image, for thedriver while achieving reduction in unnecessary stress that can be givento the driver.

In this embodiment, in one example, the predetermined abnormalityhandling process includes a process in which the display position, ofthe for-driver information image, immediately before the detectionresult of the viewpoint detector satisfies the predetermined abnormalcondition is kept.

With this arrangement, even if the viewpoint position of the drivercannot be detected or the viewpoint position of the driver is mistakenlydetected due to some causes, it is possible to avoid the visibility ofthe for-driver information image from being lowered or unnecessarystress from being given to the driver during driving 300.

In this embodiment, in one example, the predetermined abnormalityhandling process includes a process in which the for-driver informationimage is not displayed, for example, through hiding or stopping display.

With this arrangement, even if the viewpoint position of the drivercannot be detected or the viewpoint position of the driver is mistakenlydetected due to some causes, it is possible to avoid the visibility ofthe for-driver information image from being lowered or unnecessarystress from being given to the driver during driving 300.

In this embodiment, in one example, the predetermined abnormalityhandling process includes a process in which the display position of thefor-driver information image is changed to a predetermined referenceposition.

With this arrangement, even if the viewpoint position of the drivercannot be detected or the viewpoint position of the driver is mistakenlydetected due to some causes, it is possible to avoid the visibility ofthe for-driver information image from being lowered or unnecessarystress from being given to the driver during driving 300.

In this embodiment, in one example, the display controller performs thedisplay control, based on the detection result when the detection resultof the viewpoint detector does not satisfy the predetermined abnormalcondition any longer after performing the predetermined abnormalityhandling process.

With this arrangement, even in the case that the viewpoint position ofthe driver cannot be detected or the viewpoint position of the driver ismistakenly detected due to a temporary cause, it is possible to resumeafter removal of the cause the display control in which the displayposition of the for-driver information image is changed so as to changethe perception distance for the driver due to motion parallax.

In this embodiment, in one example, the viewpoint detector includes adetector that detects the viewpoint position of the driver, based on acaptured image of a head of the driver captured by an imaging unit.

With this arrangement, the viewpoint position of the driver can bedetected highly precisely.

In this embodiment, in one example, the information provision deviceincludes an illuminator that illuminates an imaging area of the imagingunit.

With this arrangement, the captured image having a constant quality canbe obtained without being largely affected by an imaging environment(for example, the difference in intensity of external light) of theimaging unit, such that a viewpoint position can be stably detected withthe influence of the imaging environment being controlled.

In this embodiment, in one example, the imaging unit is a camera thattakes an image of infrared light rays.

With this arrangement, the viewpoint position of the driver can bedetected by using a captured image (thermography) that detects farinfrared rays emitted from the head of the driver, and the viewpointposition of the driver can be detected by using an infrared image thatis not affected by visible light.

In this embodiment, in one example, the viewpoint detector includes adetector that detects the viewpoint position of the driver in thedriver's seat by using a detection result of a sensor provided on thedriver's seat of the mobile object.

Also with this aspect, the viewpoint position of the driver can bedetected.

In this embodiment, in one example, the image display is an image-lightprojection device that projects image light to a light transmissionmember so as to display the for-driver information image in thepredetermined display area 700 that the driver 300 visually recognizes,ahead in a mobile object traveling direction, via the light transmissionmember such as the windshield 302.

This arrangement allows the driver driving the mobile object to visuallyrecognize the for-driver information image without largely turning thedriver's eyes from the mobile object traveling direction.

In another embodiment, an information providing method is provided,which causes an image display to display a for-driver information imageto a driver of a mobile object. The method includes: detecting aviewpoint position of the driver; and performing a display control tochange a perception distance, of the for-driver information image, forthe driver due to motion parallax, by changing a display position of thefor-driver information image, depending on a detection result in thestep of detecting a viewpoint position. In the step of performing adisplay control, if a detection result in the step of detecting aviewpoint position satisfies a predetermined abnormal condition, apredetermined abnormality handling process is performed instead of thedisplay control.

With the present aspect, if an abnormality satisfying a predeterminedabnormal condition occurs in a detection result by the viewpointdetector, the display control is not performed in which the perceptiondistance for the driver due to motion parallax is changed. This preventsa situation from occurring in which the display position of thefor-driver information image is abnormally changed. An abnormalityhandling process having an appropriate content is performed when anabnormality occurs in the detection result by the viewpoint detector.This results in securing the visibility, of the for-driver informationimage, for the driver while achieving reduction in unnecessary stressthat can be given to the driver.

In another embodiment, a control program for causing an image display todisplay a for-driver information image to a driver of a mobile object isprovided, which performs the above-described method.

Note that the above program can be distributed or obtained, being storedin a recording medium such as a CD-ROM. Via a public telephone line oran exclusive line, the program can be distributed or obtained also bydelivering or receiving a signal on which the above program is carriedand which is transmitted by a predetermined transmission device. Whenthe program is delivered, at least part of the computer program has onlyto be transmitted in the transmission medium. That is, the transmissionmedium does not have to include all the data constituting the computerprogram at the same time. The signal on which the above program iscarried is a computer data signal embodied as a predetermined carrierwave including the computer program. A transmission method fortransmitting the computer program from the predetermined transmissiondevice includes a case of continuously transmitting or a case ofintermittently transmitting the data constituting the program.

Numerous additional modifications and variations are possible in lightof the above teachings. It is therefore to be understood that within thescope of the appended claims, the disclosure of the present inventionmay be practiced otherwise than as specifically described herein. Forexample, elements and/or features of different illustrative embodimentsmay be combined with each other and/or substituted for each other withinthe scope of this disclosure and appended claims.

Each of the functions of the described embodiments may be implemented byone or more processing circuits or circuitry. Processing circuitryincludes a programmed processor, as a processor includes circuitry. Aprocessing circuit also includes devices such as an application specificintegrated circuit (ASIC), digital signal processor (DSP), fieldprogrammable gate array (FPGA), and conventional circuit componentsarranged to perform the recited functions.

As described above, the present invention can be implemented in anyconvenient form, for example using dedicated hardware, or a mixture ofdedicated hardware and software. The present invention may beimplemented as computer software implemented by one or more networkedprocessing apparatuses. The network can comprise any conventionalterrestrial or wireless communications network, such as the Internet.The processing apparatuses can compromise any suitably programmedapparatuses such as a general purpose computer, personal digitalassistant, mobile telephone (such as a WAP or 3G-compliant phone) and soon. Since the present invention can be implemented as software, each andevery aspect of the present invention thus encompasses computer softwareimplementable on a programmable device. The computer software can beprovided to the programmable device using any storage medium for storingprocessor readable code such as a floppy disk, hard disk, CD ROM,magnetic tape device or solid state memory device.

The invention claimed is:
 1. An information provision device comprising:an image display to display a for-driver information image to a driverof a mobile object; an interface to obtain at least one of movementinformation of the mobile object and position information of the mobileobject; and circuitry to detect at least one viewpoint position of thedriver that indicates at least one position of a single eye of thedriver; control display of the for-driver information image based on thedetected at least one viewpoint position of the driver; calculate adistance of movement of the at least one viewpoint position of thedriver based on the detected at least one viewpoint position of thedriver; and change a display position of the for-driver informationimage in a direction opposite to a moving direction of the at least oneviewpoint position of the driver by a distance based on the calculateddistance of the movement of the at least one viewpoint position of thedriver.
 2. The information provision device of claim 1, wherein theinterface obtains moving-speed information of the mobile object as themovement information, and the circuitry controls display of thefor-driver information image based on the moving-speed information thatis obtained, such that the perception distance is more distant as amoving speed of the mobile object is higher and the perception distanceis shorter as the moving speed of the mobile object is lower.
 3. Theinformation provision device of claim 2, wherein the interface obtainsmoving-speed information of the mobile object as the movementinformation, and the circuitry controls display of the for-driverinformation image such that the perception distance becomes shorter whenthe obtained moving-speed information satisfies a predeterminedspeed-increase warning condition.
 4. The information provision device ofclaim 1, wherein the interface obtains the position information of themobile object, and the circuitry controls display of the for-driverinformation image such that the perception distance becomes shorter whenthe obtained position information satisfies a predeterminedspeed-increase warning condition.
 5. The information provision device ofclaim 1, wherein the interface obtains moving-speed information of themobile object as the movement information, and the circuitry controlsdisplay of the for-driver information image such that the perceptiondistance becomes longer when the obtained moving-speed informationsatisfies a predetermined slowdown warning condition.
 6. The informationprovision device of claim 1, wherein the interface obtains the positioninformation of the mobile object, and the circuitry controls display ofthe for-driver information image such that the perception distancebecomes longer when the obtained position information satisfies apredetermined slowdown warning condition.
 7. The information provisiondevice of claim 1, wherein the circuitry controls to change theperception distance in a time period equal to or longer than one second.8. The information provision device of claim 1, wherein the circuitrycauses the image display to display a plurality of types of thefor-driver information images each having a perception distancedifferent from each other, and controls display of the plurality oftypes of the for-driver information images such that the perceptiondistance of at least one type of the plurality of types of thefor-driver information images is changed.
 9. The information provisiondevice of claim 1, wherein the image display is an image-lightprojection device that projects an image light to a light transmissionmember of the mobile object so as to display the for-driver informationimage in a predetermined display area that the driver visuallyrecognizes, ahead in a mobile object traveling direction, via the lighttransmission member.
 10. The information provision device of claim 9,wherein the image display includes a projector mirror to move thepredetermined display area, and the circuitry changes a position of thepredetermined display area in addition to the display position of thefor-driver information image, based on the detected at least oneviewpoint position, so as to change the perception distance.
 11. Theinformation provision device of claim 9, wherein the image-lightprojection device displays the for-driver information image with theprojected image light as a virtual image in the predetermined displayarea, and the distance from the driver to the virtual image is equal toor greater than 5 m.
 12. The information provision device of claim 9,wherein the image-light projection device displays the for-driverinformation image in the predetermined display area by causing a lightscanner to scan and project, onto the light transmission member, theimage light emitted from a light emitter that emits image light based onimage information of the for-driver information image.
 13. Theinformation provision device of claim 1, wherein the circuitry performsabnormality handling operation in response to the result of thedetection satisfying the predetermined abnormal condition.
 14. Theinformation provision device of claim 13, wherein the predeterminedabnormal condition includes a condition that the detected at least oneviewpoint position of the driver is a viewpoint position out of apredetermined viewpoint-moving range with respect to a viewpointposition having been detected in the past.
 15. The information provisiondevice of claim 13, wherein the predetermined abnormal conditionincludes a condition that the detected at least one viewpoint positionin a predetermined period satisfies a predeterminedviewpoint-abnormally-moving condition.
 16. The information provisiondevice of claim 13, wherein, while performing the abnormality handlingoperation, the circuitry keeps a display position of the for-driverinformation image unchanged from the display position of the for-driverinformation image that is obtained immediately before the determinationindicating that the detected at least one viewpoint position satisfiesthe predetermined abnormal condition.
 17. The information provisiondevice of claim 13, wherein, while performing the abnormality handlingoperation, the circuitry changes the display position of the for-driverinformation image to a predetermined reference position.
 18. Theinformation provision device of claim 13, wherein the circuitry controlsdisplay of the for-driver information image, based on the detected atleast one viewpoint position when the detected at least one viewpointposition does not satisfy the predetermined abnormal condition afterperforming the abnormality handling operation.
 19. The informationprovision device of claim 1, wherein the circuitry is configured tochange, in response to a result of the detection failing to satisfy apredetermined abnormal condition, the display position of the for-driverinformation image so as to change a perception distance of thefor-driver information image for the driver due to motion parallax basedon the at least one of movement information and position information ofthe mobile object that is obtained.
 20. An information provision method,comprising: displaying a for-driver information image to a driver of amobile object; obtaining at least one of movement information of themobile object and position information of the mobile object; detectingat least one viewpoint position of the driver that indicates at leastone position of a single eye of the driver; controlling display of thefor-driver information image based on the detected at least oneviewpoint position of the driver; calculating a distance of movement ofthe at least one viewpoint position of the driver based on the detectedat least one viewpoint position of the driver; and changing a displayposition of the for-driver information image in a direction opposite toa moving direction of the at least one viewpoint position of the driverby a distance based on the calculated distance of the movement of the atleast one viewpoint position of the driver.
 21. The informationprovision method of claim 20, further comprising changing, in responseto a result of the detection failing to satisfy a predetermined abnormalcondition, the display position of the for-driver information image soas to change a perception distance of the for-driver information imagefor the driver due to motion parallax based on the at least one ofmovement information and position information of the mobile object thatis obtained.